Soaring Guidance Issued by NWS Grand Junction, CO
000
UXUS97 KGJT 231306
SRGGJT
Soaring Forecast
National Weather Service Grand Junction, Colorado
706 AM MDT Saturday, March 23, 2024
This forecast is for Saturday, March 23, 2024:
If the trigger temperature of 61.1 F/16.1 C is reached...then
Thermal Soaring Index....................... Excellent
Maximum rate of lift........................ 841 ft/min (4.3 m/s)
Maximum height of thermals.................. 16132 ft MSL (11293 ft AGL)
Forecast maximum temperature................... 67.0 F/19.9 C
Time of trigger temperature.................... 1130 MDT
Time of overdevelopment........................ None
Middle/high clouds during soaring window....... Broken/overcast thin middle
Surface winds during soaring window............ 20 mph or less
Height of the -3 thermal index................. 9305 ft MSL (4466 ft AGL)
Thermal soaring outlook for Sunday 03/24....... Fair
Wave Soaring Index............................. Not available
Remarks...
Sunrise/Sunset.................... 07:11:26 / 19:29:26 MDT
Total possible sunshine........... 12 hr 18 min 0 sec (738 min 0 sec)
Altitude of sun at 13:20:26 MDT... 52.04 degrees
Upper air data from rawinsonde observation taken on 03/23/2024 at 0600 MDT
Freezing level.................. 10427 ft MSL (5588 ft AGL)
Convective condensation level... 14945 ft MSL (10106 ft AGL)
Lifted condensation level....... 15334 ft MSL (10495 ft AGL)
Lifted index.................... -0.7
K index......................... +18.3
Height Temperature Wind Wind Spd Lapse Rate ConvectionT Thermal Lift Rate
ft MSL deg C deg F Dir kt m/s C/km F/kft deg C deg F Index fpm m/s
--------------------------------------------------------------------------------
50000 -57.0 -70.6 265 71 37 1.6 0.9 107.5 225.5 50.0 M M
45000 -56.2 -69.2 280 89 46 -2.3 -1.2 83.9 183.0 39.2 M M
40000 -58.0 -72.4 275 93 48 -6.1 -3.3 57.7 135.9 24.9 M M
38000 -56.7 -70.1 270 78 40 4.9 2.7 50.8 123.5 21.0 M M
36000 -57.9 -72.2 270 67 35 4.0 2.2 40.4 104.7 14.4 M M
34000 -54.7 -66.5 265 56 29 7.0 3.8 35.5 95.9 11.4 M M
32000 -50.6 -59.1 270 48 25 6.5 3.6 33.1 91.6 9.9 M M
30000 -47.5 -53.5 260 52 27 7.7 4.2 29.3 84.8 7.4 M M
29000 -45.3 -49.5 265 50 26 7.3 4.0 28.4 83.1 6.8 M M
28000 -43.1 -45.6 265 52 27 7.3 4.0 27.5 81.5 6.1 M M
27000 -40.9 -41.6 265 53 27 7.3 4.0 26.5 79.7 5.5 M M
26000 -38.7 -37.7 260 47 24 7.4 4.0 25.5 77.9 4.7 M M
25000 -36.3 -33.3 255 42 22 9.8 5.4 24.9 76.9 4.3 M M
24000 -33.4 -28.1 250 39 20 9.0 5.0 24.9 76.7 4.3 M M
23000 -30.8 -23.4 250 38 20 8.7 4.8 24.5 76.1 4.1 M M
22000 -28.2 -18.8 245 34 18 8.0 4.4 24.1 75.3 3.7 M M
21000 -25.8 -14.4 245 35 18 8.0 4.4 23.4 74.2 3.2 M M
20000 -23.4 -10.1 240 36 18 8.9 4.9 22.9 73.2 2.8 M M
19500 -22.0 -7.6 245 37 19 8.5 4.7 22.7 72.9 2.7 M M
19000 -20.6 -5.1 245 33 17 4.2 2.3 21.9 71.4 1.9 M M
18500 -19.8 -3.6 245 33 17 7.3 4.0 21.1 70.0 1.2 M M
18000 -18.7 -1.7 250 32 16 7.0 3.8 20.7 69.3 0.9 M M
17500 -17.6 0.3 245 31 16 6.9 3.8 20.2 68.4 0.5 M M
17000 -16.4 2.5 240 29 15 9.7 5.3 19.9 67.9 0.3 M M
16500 -15.1 4.8 235 32 17 7.9 4.4 19.8 67.6 0.1 M M
16000 -13.9 7.0 235 35 18 8.0 4.4 19.5 67.2 -0.1 1019 5.2
15500 -12.7 9.1 235 38 19 7.9 4.3 19.2 66.6 -0.4 969 4.9
15000 -11.6 11.1 235 38 20 7.9 4.3 18.9 66.1 -0.7 920 4.7
14500 -10.4 13.3 230 33 17 8.1 4.4 18.6 65.5 -1.0 871 4.4
14000 -9.2 15.4 230 27 14 8.3 4.6 18.4 65.1 -1.3 820 4.2
13500 -8.0 17.6 225 26 13 8.3 4.6 18.1 64.6 -1.6 769 3.9
13000 -6.7 19.9 220 24 12 8.8 4.8 18.0 64.3 -1.7 716 3.6
12500 -5.4 22.3 220 21 11 8.8 4.8 17.8 64.1 -1.9 662 3.4
12000 -4.1 24.6 230 18 9 8.8 4.8 17.7 63.8 -2.0 608 3.1
11500 -2.8 27.0 235 19 10 8.8 4.8 17.5 63.5 -2.2 554 2.8
11000 -1.5 29.3 240 20 10 8.8 4.8 17.4 63.3 -2.4 500 2.5
10500 -0.2 31.6 245 18 10 8.8 4.8 17.2 63.0 -2.6 446 2.3
10250 0.4 32.7 245 18 9 8.8 4.8 17.1 62.8 -2.7 419 2.1
10000 1.1 34.0 245 18 9 8.7 4.8 17.0 62.7 -2.7 392 2.0
9750 1.7 35.1 245 20 10 8.6 4.7 17.0 62.5 -2.8 365 1.9
9500 2.4 36.3 240 19 10 8.6 4.7 16.9 62.4 -2.9 339 1.7
9250 3.0 37.4 235 19 10 8.6 4.7 16.8 62.2 -3.0 312 1.6
9000 3.7 38.7 230 18 9 8.6 4.7 16.7 62.1 -3.1 285 1.5
8750 4.3 39.7 230 18 9 8.6 4.7 16.6 61.9 -3.2 259 1.3
8500 5.0 41.0 225 16 8 8.6 4.7 16.5 61.8 -3.3 232 1.2
8250 5.6 42.1 225 14 7 8.6 4.7 16.5 61.6 -3.4 205 1.0
8000 6.2 43.2 215 12 6 8.6 4.7 16.4 61.5 -3.5 179 0.9
7750 6.9 44.4 210 12 6 8.6 4.7 16.3 61.3 -3.6 152 0.8
7500 7.5 45.5 200 13 7 8.6 4.7 16.2 61.1 -3.7 125 0.6
7250 8.2 46.8 195 14 7 8.6 4.7 16.1 61.0 -3.8 99 0.5
7000 8.8 47.8 185 15 8 8.6 4.7 16.0 60.8 -3.9 72 0.4
6750 9.5 49.1 185 15 8 8.5 4.7 15.9 60.6 -4.0 45 0.2
6500 10.1 50.2 175 16 8 8.8 4.8 15.8 60.4 -4.1 19 0.1
6250 10.7 51.3 170 18 9 7.9 4.3 15.7 60.3 -4.2 M M
6000 11.4 52.5 165 20 10 11.3 6.2 15.6 60.1 -4.3 M M
5750 12.0 53.6 170 18 9 -1.6 -0.9 15.5 59.9 -4.4 M M
5500 11.3 52.3 165 14 7 -11.2 -6.2 14.0 57.1 -5.9 M M
5250 11.0 51.8 160 10 5 3.2 1.7 12.9 55.3 -7.0 M M
5000 11.3 52.3 140 6 3 -0.4 -0.2 12.5 54.5 -7.4 M M
* * * * * * Numerical weather prediction model forecast data valid * * * * * *
03/23/2024 at 0900 MDT | 03/23/2024 at 1200 MDT
|
CAPE... 0.0 LI... +1.6 | CAPE... +40.5 LI... +0.9
CINH... 0.0 K Index... +13.4 | CINH... -14.0 K Index... +19.7
|
Height Temperature Wnd WndSpd Lapse Rate | Temperature Wnd WndSpd Lapse Rate
ft MSL deg C deg F Dir kt m/s C/km F/kft | deg C deg F Dir kt m/s C/km F/kft
--------------------------------------------------------------------------------
50000 -58.5 -73.3 270 65 33 0.5 0.3 | -57.8 -72.0 265 63 32 1.2 0.6
45000 -57.7 -71.9 265 87 45 0.5 0.3 | -56.1 -69.0 260 84 43 1.3 0.7
40000 -57.0 -70.6 265 93 48 0.5 0.3 | -56.3 -69.3 260 98 50 -0.2 -0.1
38000 -56.3 -69.3 265 89 46 2.0 1.1 | -56.2 -69.2 260 98 50 1.5 0.8
36000 -55.1 -67.2 265 75 39 1.9 1.1 | -55.1 -67.2 260 83 43 1.5 0.8
34000 -53.8 -64.8 260 62 32 5.1 2.8 | -54.1 -65.4 255 71 36 5.1 2.8
32000 -50.4 -58.7 255 57 29 5.6 3.1 | -50.4 -58.7 250 62 32 6.1 3.4
30000 -46.9 -52.4 250 52 27 7.1 3.9 | -46.7 -52.1 240 56 29 6.8 3.7
29000 -44.8 -48.6 250 51 26 7.1 3.9 | -44.7 -48.5 240 53 27 6.8 3.7
28000 -42.7 -44.9 250 51 26 7.1 3.9 | -42.7 -44.9 235 51 26 6.8 3.7
27000 -40.5 -40.9 250 50 26 7.0 3.8 | -40.7 -41.3 235 48 25 6.6 3.6
26000 -38.1 -36.6 250 48 25 8.5 4.7 | -38.2 -36.8 235 47 24 9.0 4.9
25000 -35.6 -32.1 250 45 23 8.5 4.7 | -35.5 -31.9 235 47 24 9.0 5.0
24000 -33.1 -27.6 250 42 22 8.5 4.7 | -32.8 -27.0 235 46 24 9.1 5.0
23000 -30.0 -22.0 250 40 20 8.1 4.4 | -30.3 -22.5 235 46 23 8.0 4.4
22000 -27.6 -17.7 250 38 20 8.1 4.4 | -27.3 -17.1 235 44 23 8.0 4.4
21000 -25.2 -13.4 250 36 19 8.0 4.4 | -25.0 -13.0 235 43 22 7.7 4.2
20000 -22.8 -9.0 245 34 18 8.0 4.4 | -22.7 -8.9 230 41 21 7.5 4.1
19500 -21.6 -6.9 245 33 17 8.0 4.4 | -21.6 -6.9 230 40 21 7.5 4.1
19000 -20.4 -4.7 240 32 17 8.0 4.4 | -20.5 -4.9 230 40 20 7.5 4.1
18500 -19.2 -2.6 240 32 16 7.8 4.3 | -19.4 -2.9 230 39 20 7.0 3.9
18000 -18.1 -0.6 240 31 16 7.5 4.1 | -18.5 -1.3 230 38 19 6.2 3.4
17500 -17.0 1.4 235 31 16 7.5 4.1 | -17.6 0.3 230 37 19 6.3 3.5
17000 -15.9 3.4 235 30 16 6.6 3.6 | -16.7 1.9 230 36 19 5.4 2.9
16500 -14.9 5.2 235 30 16 6.7 3.7 | -15.9 3.4 230 35 18 5.4 3.0
16000 -13.9 7.0 235 31 16 6.3 3.5 | -15.1 4.8 230 34 18 6.2 3.4
15500 -13.0 8.6 235 31 16 6.2 3.4 | -14.1 6.6 230 33 17 6.5 3.6
15000 -12.1 10.2 230 31 16 6.4 3.5 | -13.1 8.4 230 32 16 7.0 3.8
14500 -11.1 12.0 230 31 16 6.7 3.7 | -12.0 10.4 230 30 16 8.0 4.4
14000 -10.2 13.6 230 31 16 6.9 3.8 | -10.8 12.6 230 29 15 8.0 4.4
13500 -9.1 15.6 225 31 16 7.8 4.3 | -9.5 14.9 230 28 14 8.6 4.7
13000 -8.0 17.6 225 31 16 7.8 4.3 | -8.3 17.1 230 27 14 8.6 4.7
12500 -6.8 19.8 225 30 15 8.2 4.5 | -7.0 19.4 230 26 13 8.8 4.8
12000 -5.6 21.9 225 29 15 8.2 4.5 | -5.7 21.7 225 25 13 8.8 4.8
11500 -4.4 24.1 225 28 15 7.9 4.3 | -4.4 24.1 225 24 12 9.0 5.0
11000 -3.3 26.1 220 27 14 7.9 4.3 | -3.1 26.4 225 23 12 9.0 5.0
10500 -2.2 28.0 225 26 13 7.1 3.9 | -1.8 28.8 225 22 11 7.5 4.1
10250 -1.6 29.1 225 26 13 7.8 4.3 | -1.3 29.7 225 21 11 8.5 4.7
10000 -1.0 30.2 225 25 13 10.5 5.7 | -0.6 30.9 220 21 11 11.0 6.0
9750 -0.2 31.6 220 24 12 9.9 5.4 | 0.3 32.5 220 21 11 10.2 5.6
9500 0.5 32.9 220 23 12 8.2 4.5 | 0.9 33.6 220 20 10 8.7 4.8
9250 1.1 34.0 225 23 12 8.6 4.7 | 1.6 34.9 220 20 10 9.2 5.0
9000 1.7 35.1 225 22 11 8.6 4.7 | 2.3 36.1 220 19 10 8.8 4.8
8750 3.0 37.4 220 20 10 8.4 4.6 | 2.9 37.2 215 20 10 8.9 4.9
8500 3.6 38.5 220 18 9 8.5 4.7 | 3.6 38.5 215 19 10 9.3 5.1
8250 4.3 39.7 215 17 9 8.3 4.5 | 4.3 39.7 215 19 10 8.9 4.9
8000 4.9 40.8 215 16 8 7.7 4.2 | 5.8 42.4 215 17 9 10.2 5.6
7750 5.4 41.7 210 15 8 7.5 4.1 | 6.5 43.7 215 17 9 9.1 5.0
7500 6.0 42.8 205 14 7 7.4 4.1 | 7.1 44.8 210 17 9 9.3 5.1
7250 6.5 43.7 200 13 7 6.6 3.6 | 7.8 46.0 210 17 9 8.2 4.5
7000 7.0 44.6 195 12 6 6.4 3.5 | 8.4 47.1 210 17 9 9.4 5.2
6750 7.4 45.3 190 12 6 6.8 3.7 | 9.2 48.6 210 17 9 11.0 6.0
6500 7.9 46.2 180 11 6 6.3 3.4 | 10.0 50.0 210 16 8 10.6 5.8
6250 8.4 47.1 170 10 5 6.2 3.4 | 10.8 51.4 210 16 8 11.6 6.4
6000 8.8 47.8 160 10 5 5.0 2.7 | 11.7 53.1 210 15 8 9.2 5.1
5750 9.1 48.4 165 8 4 4.1 2.2 | 12.3 54.1 210 14 7 11.5 6.3
5500 9.8 49.6 150 6 3 20.7 11.3 | 14.5 58.1 210 12 6 59.3 32.5
5250 M M M M M M M | M M M M M M M
5000 M M M M M M M | M M M M M M M
03/23/2024 at 1500 MDT | 03/23/2024 at 1800 MDT
|
CAPE... +60.1 LI... -0.5 | CAPE... +80.8 LI... -0.2
CINH... -3.8 K Index... +23.1 | CINH... -34.1 K Index... +25.2
|
Height Temperature Wnd WndSpd Lapse Rate | Temperature Wnd WndSpd Lapse Rate
ft MSL deg C deg F Dir kt m/s C/km F/kft | deg C deg F Dir kt m/s C/km F/kft
--------------------------------------------------------------------------------
50000 -57.5 -71.5 260 61 32 1.0 0.5 | -57.0 -70.6 255 58 30 1.2 0.6
45000 -55.9 -68.6 255 82 42 1.1 0.6 | -55.2 -67.4 255 76 39 1.2 0.6
40000 -55.8 -68.4 255 101 52 0.0 0.0 | -55.0 -67.0 250 98 51 -0.0 -0.0
38000 -55.5 -67.9 255 103 53 1.6 0.9 | -54.8 -66.6 250 101 52 1.1 0.6
36000 -54.5 -66.1 250 92 47 1.7 0.9 | -54.1 -65.4 250 88 45 1.1 0.6
34000 -53.4 -64.1 250 79 41 3.8 2.1 | -53.5 -64.3 250 76 39 1.2 0.7
32000 -50.3 -58.5 245 69 35 5.0 2.8 | -51.4 -60.5 245 63 32 3.7 2.0
30000 -47.3 -53.1 240 59 31 6.6 3.6 | -49.1 -56.4 235 51 26 4.7 2.6
29000 -45.2 -49.4 240 58 30 7.0 3.9 | -46.9 -52.4 235 49 25 8.2 4.5
28000 -43.1 -45.6 240 56 29 7.0 3.9 | -44.4 -47.9 235 48 25 8.1 4.5
27000 -41.0 -41.8 235 55 28 6.9 3.8 | -42.0 -43.6 235 47 24 8.2 4.5
26000 -38.5 -37.3 235 53 27 8.9 4.9 | -38.8 -37.8 235 45 23 8.6 4.7
25000 -35.9 -32.6 235 51 26 8.9 4.9 | -36.2 -33.2 235 43 22 8.6 4.7
24000 -33.2 -27.8 235 48 25 8.9 4.9 | -33.6 -28.5 235 41 21 8.7 4.8
23000 -30.7 -23.3 235 47 24 8.2 4.5 | -31.1 -24.0 235 40 20 8.5 4.7
22000 -27.7 -17.9 235 47 24 8.1 4.5 | -28.6 -19.5 235 38 20 8.5 4.7
21000 -25.3 -13.5 230 47 24 7.5 4.1 | -26.0 -14.8 235 37 19 8.5 4.7
20000 -23.3 -9.9 230 45 23 6.8 3.7 | -23.6 -10.5 230 36 19 8.2 4.5
19500 -22.2 -8.0 230 44 23 6.8 3.7 | -22.4 -8.3 230 36 19 8.2 4.5
19000 -21.2 -6.2 230 43 22 6.8 3.7 | -21.1 -6.0 230 36 18 8.2 4.5
18500 -20.2 -4.4 230 42 22 6.9 3.8 | -19.9 -3.8 225 35 18 8.3 4.6
18000 -19.2 -2.6 230 40 21 7.2 3.9 | -18.7 -1.7 225 35 18 7.8 4.3
17500 -18.1 -0.6 225 39 20 7.1 3.9 | -17.6 0.3 225 35 18 7.9 4.3
17000 -17.1 1.2 225 37 19 7.7 4.2 | -16.4 2.5 220 35 18 7.6 4.2
16500 -15.9 3.4 225 36 18 7.8 4.3 | -15.3 4.5 220 35 18 7.4 4.1
16000 -14.8 5.4 225 34 18 7.9 4.3 | -14.2 6.4 220 34 18 7.4 4.1
15500 -13.6 7.5 225 33 17 8.0 4.4 | -13.2 8.2 215 34 18 7.3 4.0
15000 -12.4 9.7 220 32 16 8.0 4.4 | -12.1 10.2 215 34 17 7.3 4.0
14500 -11.3 11.7 220 31 16 8.0 4.4 | -11.0 12.2 215 34 17 8.0 4.4
14000 -10.1 13.8 220 30 15 8.0 4.4 | -9.8 14.4 215 33 17 7.9 4.3
13500 -8.9 16.0 220 29 15 8.5 4.6 | -8.6 16.5 210 33 17 8.4 4.6
13000 -7.6 18.3 215 28 14 8.3 4.6 | -7.4 18.7 210 33 17 8.4 4.6
12500 -6.3 20.7 215 27 14 9.2 5.1 | -6.1 21.0 210 32 17 8.4 4.6
12000 -5.0 23.0 215 27 14 9.1 5.0 | -4.9 23.2 210 32 16 8.4 4.6
11500 -3.6 25.5 215 26 13 9.3 5.1 | -3.6 25.5 210 31 16 8.6 4.7
11000 -2.2 28.0 215 26 13 9.4 5.2 | -2.3 27.9 210 31 16 8.7 4.8
10500 -0.9 30.4 215 25 13 8.0 4.4 | -1.1 30.0 210 30 15 7.6 4.1
10250 -0.3 31.5 215 24 13 9.2 5.0 | -0.6 30.9 210 29 15 7.8 4.3
10000 0.5 32.9 215 25 13 11.5 6.3 | 0.1 32.2 210 29 15 9.8 5.4
9750 1.4 34.5 215 25 13 10.8 5.9 | 0.8 33.4 210 29 15 9.9 5.4
9500 2.1 35.8 215 25 13 9.6 5.3 | 1.5 34.7 210 28 15 8.8 4.8
9250 2.8 37.0 215 24 12 9.8 5.4 | 2.2 36.0 215 27 14 8.4 4.6
9000 3.6 38.5 215 24 12 10.0 5.5 | 2.8 37.0 215 27 14 8.3 4.5
8750 4.3 39.7 215 24 13 10.2 5.6 | 4.0 39.2 215 26 13 8.9 4.9
8500 5.8 42.4 215 24 12 10.2 5.6 | 4.7 40.5 215 25 13 9.3 5.1
8250 6.6 43.9 215 23 12 9.6 5.3 | 5.4 41.7 215 25 13 8.1 4.5
8000 7.3 45.1 215 23 12 9.6 5.3 | 5.9 42.6 220 24 12 7.6 4.2
7750 8.0 46.4 215 23 12 10.1 5.5 | 6.5 43.7 220 23 12 8.4 4.6
7500 8.8 47.8 215 22 12 10.5 5.7 | 7.1 44.8 220 22 11 8.3 4.6
7250 9.5 49.1 215 22 11 8.6 4.7 | 7.8 46.0 220 21 11 8.0 4.4
7000 10.1 50.2 215 22 11 8.9 4.9 | 8.3 46.9 220 21 11 8.5 4.7
6750 10.9 51.6 215 21 11 11.1 6.1 | 9.0 48.2 220 20 10 9.3 5.1
6500 11.7 53.1 215 20 10 10.7 5.9 | 9.7 49.5 225 18 9 8.9 4.9
6250 12.5 54.5 215 20 10 10.7 5.9 | 10.3 50.5 225 17 9 9.7 5.3
6000 13.4 56.1 215 19 10 14.6 8.0 | 11.1 52.0 225 17 9 11.9 6.5
5750 14.8 58.6 215 17 9 22.0 12.0 | 12.1 53.8 225 15 8 13.3 7.3
5500 16.1 61.0 215 15 8 8.6 4.7 | 13.0 55.4 225 13 7 11.6 6.4
5250 M M M M M M M | M M M M M M M
5000 M M M M M M M | M M M M M M M
________________________________________________________________________________
This product is issued twice per day, once by approximately 0630 MST/0730 MDT
(1330 UTC) and again by approximately 1830 MST/1930 MDT (0130 UTC). It is not
continuously monitored nor updated after its initial issuance.
The information contained herein is based on rawinsonde observation and/or
numerical weather prediction model data taken at Walker Field in Grand
Junction, Colorado at
North Latitude: 39 deg 07 min 00.001 sec
West Longitude: 108 deg 31 min 59.998 sec
Elevation: 4839 feet (1475 meters)
and may not be representative of other areas along the Western Slope of
Colorado. Note that some elevations in numerical weather prediction models
differ from actual station elevations, which can lead to data which appear
to be below ground. Erroneous data such as these should not be used.
The content and format of this report as well as the issuance times are subject
to change without prior notice. Comments and suggestions are welcome and should
be directed to one of the addresses or phone numbers shown at the bottom of this
page. To expedite a response to comments, be sure to mention your interest in
the soaring forecast.
DEFINITIONS:
CAPE (Convective Available Potential Energy) - An integrated measure of the
energy available for convective development, also known as the positive
area on a thermodynamic diagram. Units are Joules per kilogram. Larger
values are indicative of greater instability and the possibility of
stronger convective activity, including thunderstorms. Values around or
greater than 1000 suggest the possibility of severe weather should
convective activity develop.
CINH (Convective Inhibition) - An integrated measure of the amount of energy
needed to initiate convective activity, also known as the negative area on
a thermodynamic diagram. Units are Joules per kilogram. The more negative
this number, the more energy is required to initiate convection. This
inhibitive energy can be overcome through surface heating, cooling aloft,
lifting mechanisms (orographic, frontal, gravity waves, etc.)
Convective Condensation Level - The height to which an air parcel possessing the
average saturation mixing ratio in the lowest 4000 feet of the airmass,
if heated sufficiently from below, will rise dry adiabatically until it
just becomes saturated. It estimates the base of cumulus clouds that are
produced by surface heating only.
Convection Temperature (ConvectionT) - The surface temperature required to make
the airmass dry adiabatic up to the given level. It can be considered a
"trigger temperature" for that level.
Freezing Level - The height where the temperature is zero degrees Celsius.
Height of Stable Layer - The height (between 12,000 and 18,000 feet above
mean sea level) where the smallest lapse rate exists. The location and
existence of this feature is important in the generation of mountain
waves.
K Index - A measure of stability which combines the temperature difference
between approximately 5,000 and 18,000 feet above the surface, the amount
of moisture at approximately 5,000 feet above the surface, and a measure
of the dryness at approximately 10,000 feet above the surface. Larger
positive numbers indicate more instability and a greater likelihood of
thunderstorm development. One interpretation of K index values regarding
soaring in the western United States is given in WMO Technical Note 158
and is reproduced in the following table:
below -10 no or weak thermals
-10 to 5 dry thermals or 1/8 cumulus with moderate thermals
5 to 15 good soaring conditions
15 to 20 good soaring conditions with occasional showers
20 to 30 excellent soaring conditions, but increasing
probability of showers and thunderstorms
above 30 more than 60 percent probability of thunderstorms
Lapse Rate - The change with height of the temperature. Negative values indicate
inversions.
Lifted Condensation Level - The height to which an air parcel possessing the
average dew point in the lowest 4000 feet of the airmass and the forecast
maximum temperature must be lifted dry adiabatically to attain saturation.
Lifted Index (LI) - The difference between the environmental temperature at a
level approximately 18,000 feet above the surface and the temperature of
an air parcel lifted dry adiabatically from the surface to its lifted
condensation level and then pseudoadiabatically thereafter to this same
level. The parcel`s initial temperature is the forecast maximum
temperature and its dew point is the average dew point in the lowest 4000
feet of the airmass. Negative values are indicative of instability with
positive values showing stable conditions.
Lift Rate - An experimental estimate of the strength of thermals. It is
computed the same way as the maximum rate of lift but uses the actual
level rather than the maximum height of thermals in the calculation.
Also, none of the empirical adjustments based on cloudiness and K-index
are applied to these calculations.
Maximum Height of Thermals - The height where the dry adiabat through the
forecast maximum temperature intersects the environmental temperature.
Maximum Rate of Lift - An estimate of the maximum strength of thermals. It
is computed from an empirical formula which combines the expected maximum
height of thermals with the difference in the environmental temperatures
between the maximum height of thermals and the temperature 4,000 feet
above the ground. After this computation, further empirical adjustments
are made based on the value of the K-index and the amount and opacity of
middle and high level cloudiness expected between the time of trigger
temperature and the time of overdevelopment.
Middle/High Clouds - The amount and opacity of middle (altostratus, altocumulus)
or high (cirrus, cirrostratus, cirrocumulus) clouds. Broken means that
between 60% and 90% of the sky is covered by the cloud, with overcast
conditions occurring when more than 90% of the sky is covered by the cloud.
Thin implies that the clouds are predominantly transparent, meaning that
some sunlight is reaching the ground, in contrast to opaque which suggests
that little sunlight is reaching the ground.
Potential Height of Wave - The minimum of the following two heights:
1. Level above the height of stable layer (or 14,000 feet if none exists)
where the wind direction changes by 30 degrees or more
2. Level above the height of stable layer (or 14,000 feet if none exists)
where the wind speed no longer increases with height
PVA/NVA - Positive vorticity advection (PVA)/negative vorticity advection (NVA)
on the 500 millibar isobaric surface (approximately 18,000 feet above mean
sea level). Weak PVA has been shown to assist in mountain wave soaring.
Soaring Window - The time between the time the trigger temperature is reached
and the time of overdevelopment.
Thermal Index - The difference between the environmental temperature and the
temperature at a particular level determined by following the dry adiabat
through the forecast maximum temperature up to that level. Negative values
are indicative of thermal lift.
Thermal Soaring Index - An adjective rating (for sailplanes) based on the
computed maximum rate of lift, and the wind speed and middle and high
cloud cover expected during the soaring window (the time of the trigger
temperature and the time of overdevelopment) according to the following:
Maximum rate of lift Adjective Rating
>= 800 fpm Excellent
>= 400 and < 800 fpm Good
>= 200 and < 400 fpm Fair
< 200 fpm Poor
Time of Overdevelopment - The time one or more of the following phenomena,
which essentially shut off thermal lift, is expected to occur:
1. formation of broken to overcast convective cloud cover
2. formation of scattered to numerous downbursts
3. initiation of widespread precipitation
Time of Trigger Temperature - The time the surface temperature is expected to
reach the trigger temperature.
Trigger Temperature - The surface temperature required to make the first 4000
feet of the atmosphere dry adiabatic.
Wave Soaring Index - An empirical, adjective rating (for sailplanes) which
attempts to combine a variety of phenomena important in mountain wave
soaring into a single index number. Objective points are assigned to
these phenomena: wind speed and direction at 14,000 ft MSL, the static
stability in the 12,000-18,000 ft MSL layer, the wind speed gradient above
the stable layer, jet stream location and frontal and upper trough
movements.
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